The findings come from a survey of 679 internists and rheumatologists. Doctors in these specialties often see patients with chronic illnesses or chronic pains that are difficult, if not impossible, to cure. Sometimes fake medicine -- placebos -- make such patients feel better.

Fake drugs can have very real benefits. It's called the placebo effect. In clinical trials, many patients who receive placebos do better than real-world patients who get no treatment at all, notes study researcher Jon C. Tilburt, MD.

"Twenty to thirty percent of the benefit seen in rheumatism drug studies are due to the placebo effect. Real changes in health go along with the belief that patients will get better," Tilburt tells WebMD.

Tilburt and colleagues asked the doctors a series of questions, each a bit more blunt than the last:

If a clinical trial showed a sugar pill was better than no treatment for fibromyalgia, would you recommend sugar pills to fibromyalgia patients? Yes, 58% of the doctors said.

Do you ever actually recommend treatments primarily to enhance a patient's expectations? Yes, 80% of the doctors said.

In the last year, did you recommend a placebo treatment to a patient? Yes, 55% of the doctors said.

What did the doctors actually tell their patients? Over two-thirds of those who prescribed placebos told patients they were getting "medicine not typically used for your condition but which might benefit you."

Is it "appropriate" to fool patients this way? Yes, 62% of the doctors said.

"I don't think doctors have anything but the patients' best interest in mind when they give a placebo prescription," says Tilburt. "They are thinking about both the physical and psychological well-being of the patient."

The hard-to-accept truth is that doctors don't have proven treatments for many of the ills that plague their patients.

"With untreatable conditions or chronic conditions when we have run out of treatments, doctors are willing to try virtually anything -- if they are convinced it is safe -- to make the patient feel better, even if the mechanism is a psychological mechanism," Tilburt says.